Drawer interlocking means for cabinets and the like



July 8, 1969 A. R. OLREE DRAWERINTERLOCKING MEANS FOR CABINETS AND THE LIKE Filed June 2a. 1967 Sheet of3 YBY M July 8, 1969 A. R. OLREE DRAWER INTERLOCKING MEANS FOR CABINETS AND THE' LIKE Filed June 28. 1967 Sheet INVENTOR.

, App/4A! P. alias BY a, I

/ VIII! July 8, 1969 DEAWER INTERLOCKING MEANS FOR CABINETS AND THE LIKE Filed June 28, 1967 A. R. OLREE Sheet .3 of 3 147' ramI CV United States Patent 3,454,320 DRAWER INTERLOCKING MEANS FOR CABINETS AND THE LIKE Adrian R. Olree, Caledonia, Mich., assignor to Steelcase, Inc., Grand Rapids, Mich., a corporation of Michigan Filed June 28, 1967, Ser. No. 649,600 Int. Cl. E05c /04 US. Cl. 312-217 25 Claims ABSTRACT OF THE DISCLOSURE A rotatably-mounted rod positioned perpendicular to the drawers in a file cabinet and located adjacent such drawers, with a number of pairs of angularly-disposed finger elements attached to the rod, each pair extending laterally of the rod in juxtaposition to one of the drawers in the cabinet. Each drawer has an abutment on its side which is in alignment with the finger elements extending laterally toward that drawer, with the arrangement being such that when any given drawer is drawn out of the cabinet to an open position the abutment means on such drawer will come into contact with and push against a first one of the finger elements in the adjacent pair thereof, to thereby rotate the rod, somewhat in the manner of a turnstile. Such rotation of the rod places a leading edge of each of the first finger elements in each pair in contact with a fixed part of the cabinet, to limit rotation of the rod. Also, the second finger element in each pair is moved during this rotation into alignment with the abutment means on the drawer adjacent thereto, such that drawers remaining in the cabinet cannot then be withdrawn until the open drawer is first closed. Further, each of the aforesaid first finger elements in each pair thereof is elevated somewhat above the other such element in each pair, so as to meet the forward portion of the abutment on the corresponding drawer near the upper extremity of such abutment as the drawer carrying the latter is opened. Such abutments have a vertically sloping rearward portion which slides beneath and operates to lift the aforesaid first element, and thereby lift the entire rod carrying all of the finger elements, to permit the closing of a drawer under conditions wherein the first finger element would otherwise directly block the abutment and prevent closing of the drawer.

Background of the invention This invention relates to filing cabinets and the like of the type having a plurality of drawers arranged in linear alignment with each other, and more particularly it relates to a means for interlocking the drawers within such a cabinet so that once a first given drawer has been opened by extending it from the cabinet, other drawers are prevented from being so extended.

Problems have always been encountered in the use of vertical filing cabinets when more than a single one of the upper drawers is opened by withdrawing such drawer from the cabinet. The opening of two or more drawers may occur either deliberately or inadvertently, but whenever it does occur the entire filing cabinet is very likely to be so unbalanced by the weight of the loaded drawers jutting out from the top of the cabinet that the entire cabinet is overturned, often with considerable injury to persons or property in the vicinity.

A variety of prior devices have been provided to overcome the foregoing problem by locking closed drawers into the cabinet whenever a given drawer is drawn open, thereby permitting only one drawer at a time to be opened. Such prior devices generally include mechanisms of a type having either a longitudinally slidable or a rotary Patented July 8, 1969 ice member carrying a number of individual latch elements, with at least one such element for each drawer. Such prior devices have met with varying degrees of success, but most of them have been characterized by overly complex structural features, including various different springs and a number of different movable elements, for example. Such complexity is not really consistent with the simplicity and singleness of purpose which such a locking or interlocking mechanism should have, and consequently the aforementioned prior devices have been subject to malfunction and breakage, and were also characterized by excessive manufacturing and installation costs.

Summary of the invention The present invention provides an interlock mechanism for the drawers of a file cabinet or the like which is of extremely high reliability and yet of an extremely simplified nature from a purely structural point of view. The device of the invention is thoroughly positive in action, and it virtually eliminates the possibility of any malfunction or improper operation.

Briefly stated, the interlock means of the invention comprises an elongate rod which is mounted in the file cabinet perpendicular to the aligned drawers therein and adjacent thereto, for rotary movements about its own longitudinal axis. This rod has a plurality of certain structural formations on it, each located in juxtaposition to one of the drawers. These structural formations each define a plurality of camming or operative surfaces, including a first such surface arranged to be contacted and pushed in a rotary path about the aforesaid rod by an abutment carried on the drawer nearest such surface, so that the latter is thus moved out of the way of the abutment. This rotation of the aforesaid rod brings it to a point where certain stop or blocking surfaces defined by each of said structural formations are moved into contact with interior portions of the cabinet, to thereby limit the allowable rotation of the rod at that point. At .this limited position of the rod certain interlock surfaces defined by each of the aforesaid structural formations are positioned in direct alignment with and ahead of the abutment means on all drawers which are not yet opened, thereby blocking all such drawers so that they cannot then be opened. However, secondary camming surfaces defined by the structural formations on the rod are under these circumstances located in alignment with the rearward side of the abutment means on the drawer initially opened, so that when such drawer is closed the abutment means thereon contacts such secondary camming surface and rotates the elongate rod back to its initial position, in which any drawer may be opened.

Structural features of the invention and the complete nature thereof will become increasingly apparent following a consideration of the ensuing specification and the appended claims in which the invention is defined, particularly When taken in conjunction with the accompanying illustrative drawings setting forth a preferred embodiment of the invention.

Brief description of the drawings FIG. 1 is a fragmentary lateral perspective view of a typical vertical filing cabinet incorporating the drawer interlock structure of the invention;

FIG. 2 is an enlarged frontal perspective view of a single first element of the interlock structure;

FIG. 3 is a rearward perspective view of the element of FIG. 2, showing also the mounting and attachment of the same;

FIG. 4 is an enlarged perspective view of another element of the interlock structure;

FIG. 5 is a side elevation of the element of FIG. 4;

FIG. 6 is an enlarged fragmentary sectional plan view taken through the horizontal plane VIVI of FIG. 1, with the drawer in a closed position;

FIG. 6a is a fragmentary sectional elevation taken through the vertical plane VIaVIa of FIG. 6;

FIG. 7 is a sectional plan view similar to that of FIG. 6, but showing the drawer in an open position and the resulting movement of the interlock structure;

FIG. 7a is a fragmentary sectional elevation taken through the vertical plane VIIa--VIIa of FIG. 7;

FIG. 8 is a sectional plan view similar to that of FIG. 7, but showing the interlock position when another drawer has been opened;

FIG. 8a is a fragmentary sectional elevation taken through the vertical plane VIIIa-VIIIa of FIG. 8;

FIG. 9 is an enlarged overhead sectional plan view taken through the horizontal plane IXIX of FIG. 1 and showing the top of the interlock device, with phantom lines indicating the movement thereof during the opening of a drawer;

FIG. 10 is an enlarged sectional plan view similar to FIG. 7, but showing a different relative position of the interlock structure;

FIG. 10a is a sectional elevation taken through the vertical plane Xa-Xa of FIG. 10;

FIG. 11 is an enlarged sectional plan view similar to FIG. 10, but showing the closing of the drawer from that position; and

FIG. 11a is a sectional elevation taken through the vertical plane XIaXIa of FIG. 11.

Description of a preferred embodiment Referring now in more detail to the drawings, a typical vertical file cabinet 10 is illustrated generally in FIG. 1, in which a number of file drawers 12 are mounted in a spaced, vertically aligned relation upon rail structures 14 which may be of a typical type and which, as will be understood, permit horizontal movement of each drawer so that the same may be withdrawn from the cabinet to open the drawer. The interlock means of the invention has a primary structural component 16 comprising an elongate vertical rod which is mounted for rotary movement about its longitudinal axis within the cabinet 10. As indicated in FIG. 1, the rod 16 has certain structural formations 18 thereon which are located adjacent each of the drawers 12, and each drawer has an abutment means 20 attached thereto in immediate juxtaposition to each of the structural formations 18 on the elongate rod.

The structural formations 18 illustrated generally in FIG. 1 are identical, and one such formation is seen in more detail in FIGS. 2 and 3. Each such formation basically comprises an angular sheet metal component defining a pair of finger elements 22 and 24 which are disposed at substantially right angles to each other. Further, finger element 22 is elevated above the plane of finger 24, being offset therefrom by a short vertical segment 23, for purposes to be noted in more detail subsequently. An aperture 25 (FIG. 2) is formed through each structure 18, between fingers 22 and 24 and generally adjacent vertical segment 23. The elongate rod 16 noted previously passes vertically through aperture 25, and each structural formation 18 is secured in direct vertical alignment with each other to the rod 16 at a desired position therealong, preferably by spot-welding the rod to the formation at the vertical segment 23 of the latter.

As indicated in FIG. 3, the rod 16 is mounted and supported in position by means of angle brackets 26 which have an appropriate aperture 27 in the horizontal portion thereof for receiving the rod. Preferably, the brackets 26 are slotted from one edge extremity to their aperture 27, and the rod 16 is necked down at 17, so that the rod may be slid sideways into position in the aperture 27. As will be understood, the vertical portion of the angle bracket 26 serves to secure the bracket to a side wall of the cabinet 10 in a desired manner, whereas the horizontal portion of the bracket, in which the aforesaid aperture 27 is formed, is disposed immediately beneath finger element 24, to support the latter as it slides thereupon when the rod 16 is rotated.

The abutment means 20 carried by each of the drawers 12 is seen in more detail in FIGS. 4 and 5, from which it will be noted that this is basically a V-shaped element, having generally fiat, coplanar end extremities 20a and 2012 by which it is attached to a drawer 12, and also having angularly disposed forward and rearward side portions 28 and 30, respectively, which give the abutment element its aforesaid V-shaped configuration. The to edge of the abutment element 20 declines vertically rearwardly of the forward end portion 20b thereof, i.e., over the angular sides 28 and 30 and over the rearward end extremity 20a. The purpose for this will also be seen more fully hereinafter.

In FIGS. 6 and 6a the normal initial relationship of a drawer 12, the abutment means 20 carried thereby, and the vertical rod 16 and one of the structural formations 18 attached thereto is illustrated, in connection with the side 10a of the file cabinet 10 which is located adjacent the other component structures just noted. That is, in the aforesaid normal initial position, the drawer 12 is closed and the abutment means 20 carried thereby is located slightly rearwardly of the vertical rod 16; also, finger element 24 of the structural formation 18 is generally parallel to and touching cabinet wall 10a, whereas finger element 22 extends laterally inwardly of wall 10a and is located immediately ahead of the forward angular side 28 of the abutment element 20.

As may be seen in FIGS. 1 and 9, the upper extremity of the vertical rod 16 has a crank-like or laterally offset portion 16a which extends radially away from the rod, preferably above the uppermost drawer 12. A coil spring 32 is connected between the outer end of this offset portion 16a and a bracket 34 secured in the front corner of the file cabinet, against side 10a thereof. The structural formations 18 are arranged on rod 16 with respect to the offset portion 16a thereof such that the offset portion is more-or-less in vertical alignment with the several finger elements 24. That is, in the initial position shown in FIG. 6, finger 24 is oriented generally parallel or at a very slight angle to the side 10a of the cabinet, and what is referred to herein as an interlock surface or portion 124, defined by one side edge of finger 24, touches the inner surface of wall 10a; in this position, the offset portion 16a of rod 16 is oriented at a slight angle to cabinet wall 10a, with the outer end of the offset portion touching, or almost touching, cabinet wall 10a. The rod 16 is spaced from side 10a at least slightly further than is the attachment point of the spring 32 to the bracket 34; consequently, in the aforesaid initial position the axis of spring 32 lies to the outside of the longitudinal axis of rod 1 6. Therefore, in this position the spring 32 pulls offset portion 16a at least lightly toward wall 10a, to maintain the interlock surface 124 on each of the finger elements 24 in abutting contact with side wall 10a of the cabinet. This is the basic purpose of this spring.

The two opposite side edges of each finger element 22 define surfaces or portions which are res-pectievly referred to herein as a first camming surface, designated 122, and an indexing and blocking surface, designated 222 (FIGS. 6 and 6a). When any drawer 12 is withdraw from the cabinet to an open position, it moves forward from the position seen in FIGS. 6 and 6a to that seen in FIGS. 7 and 7a. During this movement, the forward angular side 28 of the abutment means 20 comes into contact with and pushes against the aforesaid first camming surface 122 on finger element 22, to rotate the entire structural formation 18 and also the vertical rod 16 secured thereto a clockwise direction (as seen from overhead), to the position seen in FIG. 7.

When any drawer 12 is opened and the rod 16 is rotated in this manner, the offset portion 16a of the rod is similarly moved in a clockwise direction. At first, this motion is against the force exerted by spring 32; how ever, after a brief rotation has occurred, the axis of spring 32 will have moved across the axis of rod 16 in an over-center operation. As soon as this occurs, the spring 32 begins to pull in the opposite direction on the offset 16a, thereby tending or helping depending on the amount of spring force which this spring exerts, to rotate the rod 16 and also each of the structural formations 18 thereon to the position shown in FIG. 7, wherein the indexing and blocking surface 222 of each finger element 22 lies in direct contact with cabinet Wall 1011 to thereby limit the allowable rotation of the rod 16 and that of each of the structural formations 18 secured thereto. Once again, spring 32 holds rods 16 in the position wherein its rotation is limited, to thereby fulfill the basic function for this spring.

Under the circumstances just described, each drawer 12 within the file cabinet which is not open when a given other drawer is opened is locked within the cabinet and prevented from being opened, due to the presence of the interlock surface 124 defined by each finger element 24 immediately in front of the abutment means 20 on each drawer. As shown in FIGS. 8 and 8a, if any such closed drawer is then attempted to be drawn open, the forward side 28 of the abutment means thereon will come into abutting contact with the interlock surface 124 located immediately ahead of it. Since the indexing and blocking surface 222 of each finger element 22 is then in direct abutment against cabinet wall 10a none of the structural formations 18 can rotate clockwise any further; consequently, the interlock surfaces 124 of the various finger elements 24 stop each drawer and prevent each from being opened.

When a drawer which has been opened is closed, the rearward angular side 30 on the abutment means 20 of such drawer comes into contact with what is referred to herein as a second cam portion or surface 224, formed on the side edge of finger element 24 which is opposite the aforesaid interlock surface 124 thereof. This may be seen in FIGS. 7 and 7a. Upon further closing of such drawer, side 30 of the abutment means thereon pushes finger element 24 in a counterclockwise direction by bearing against the aforesaid second camming surface 224. This in essence reverses the previous rotation of the rod 16 and the various structural formations 18 thereon, to return the rod and the various structural formations thereon to their respective initial position, as seen in FIG. 6. That is, the stuctural formations 18 are rotated in a counterclockwise direction, which moves the offset portion 16a of rod 16 back toward the position seen in FIG. 9 against the tension of spring 32. Of course, once the axis of spring 32 swings rightwardly across the axis of rod 16, this spring will once again urge the rod in a counterclockwise direction, tending or helping to bring it to its original position, where the interlock surface 124 on each finger element 24 is once again in contact with wall 10a of the cabinet. As before, the spring will retain the rod in this position. At this point, any of the drawers 12 in the file cabinet may be opened, since nothing prevents such opening. However, upon opening any single drawer, the clockwise rotation of the vertical rod 16 noted previously will once again occur, as a result one of the first camming surfaces 122 on one of the finger elements 22 having been pushed forward by the corresponding abutment means 20 on the particular drawer which is opened.

As will be apparent from the foregoing discussion, it is possible to open at one time more than one drawer of a cabinet equipped with the present interlock means, if such drawers are opened simultaneously. If under such circumstances only one of these drawers is then closed, the various structural formations 18 will have been returned to their initial position (seen in FIG. 6), even though one of the drawers still remains in an open position. Clearly, if only the construction already described were present, this open drawer could not then be closed, since the indexing and blocking surface 222 on each structural formation 18 is oriented as seen in FIGS. 10 and 10a, i.e., immediately behind the rearward side 30 of the abutment means 20 on such drawer.

It is at this point that the elevation of finger element 22 above finger element 24 and the inclined upper edge surface of the abutment means 20, noted previously, becomes important. With this inclining edge configuration, the indexing and blocking surface 222 on finger element 22 does not actually strike the outwardly-protruding angular forward side 28 of the abutment means 20 and prevent the drawer from being closed. On the contrary, an open drawer can be closed under these circumstances, due to the following operation. As the open drawer is pusher toward a closed position, the sloping upper edge 120 of the abutment means 20 initially comes into contact with the underside of the relatively elevated finger element 22 (FIG. 10a).

Upon further closing of the drawer, the aforesaid sloping edge 120 on the abutment means 20 acts as a cam in raising the finger element 22 and the entire structural formation 18 of which such finger is a part, as well as the rod 16 and all of the different structural formations 18 located thereupon, since each such formation is fixedly secured to the rod 16. This upward movement of the rod is provided for by its mounting in the various angle brackets 26 (FIG. 3) which hold the rod in a rotatable manner and support it vertically beneath each of the finger elements 24, so that the rod cannot slip downwardly. However, nothing prevents it from being moved upward in the manner just stated, even though the tension of coil spring 32 at the top of the rod must first be stretched or extended at least slightly. This may be a very light spring, however, and accomplishing the latter need not be a difficult matter.

Thus, the abutment means 20 slips beneath the finger element 22 without changing the rotational position thereof, as indicated in FIGS. 11 and 11a, until the drawer is once again in a fully closed position. At this point, the abutment means 20 is located rearwardly of the finger element 22 (as shown in FIGS. 6 and 6a) and consequently the rod 16 slips back downward to its initial position, assisted by the tension of spring 32, which has been brought into existence or (perhaps) increased by the upward movement of the rod. Thus, both the force of gravity and the downward pulling of spring 32 return the rod 16 to its initial position, wherein the forward portion 28 of the various abutment means on each ofthe drawers is in direct alignment with the first camming surface 122 on each of the finger elements 22 disposed immediately forward of such abutment means.

As has now been fully set forth, the interlock means of the invention positively prevents the opening of drawers in a file cabinet once one such drawer has been opened, to thereby greatly increase the safety of using the file cabinet, by in effect preventing the cabinet from being tipped over by the weight of opened drawers. The blocking of each closed drawer is absolutely positive, since an integral structural element or formation blocks each individual drawer by in effect wedging its angularlydisposed finger elements between the cabinet and the drawer. That is to say, a single indexing and blocking surface located anywhere along the rod 16 might be used if separate interlock surfaces secured to the vertical rod were still utilized and disposed ahead of the abutment means on each drawer. However, this would give rise to torsion forces acting on the rod between such a single indexing and blocking surface and the various interlock surfaces. No such forces are created in accordance with the present preferred embodiment, however, since each drawer is independently blocked in a closed position by a separate blocking or interlocking entity. As will be apparent, the operation of the present interlock device is essentially foolproof, is rapid, and is positive in every re spect.

It is entirely conceivable that upon examining the foregoing disclosure, those skilled in the art may devise embodiments of the concept involved which differ somewhat from the embodiment shown and described herein, or may make various changes in structural details to the present embodiment. Consequently, all such changed embodiments or variations in structure as utilize the concepts of the invention and clearly incorporate the spirit thereof are to be considered as within the scope of the claims appended herebelow.

I claim:

1. In a file cabinet or the like of the type having plural drawers arranged in linear alignment with each other, the improvement consisting of interlock means for preventing the opening of other drawers after a first drawer has been opened, said interlock means comprising: an elongate rod mounted in said cabinet perpendicular to and adjacent said drawers for rotary movements about its own longitudinal axis; said rod having structural formations thereon defining a first series of camming surfaces, with at least one such camming surface located in lateral juxtaposition to each of said drawers; abutment means on each of said drawers, including forward and rearward portions; said forward portion on each drawer arranged to contact the particular camming surface in said first series thereof which is juxtaposed to such drawer and push against such surface to move the structural formation defining it and thereby rotate said rod in a first direction as such drawer is withdrawn from said cabinet toward an open position; said structural formations further defining at least one indexing and blocking surface for contacting a portion of such cabinet upon a predetermined extent of such rotation to thereby limit such rotation; said structural formations additionally defining a series of interlock surfaces, with at least one such surface located in lateral juxtaposition to each of said drawers and, at said limit of rotation of said rod, in direct alignment with said abutment means on said drawers, such that upon opening any one drawer any other drawer not yet extended to an open position is prevented from being so extended by contact of the abutment means thereon with such interlock surface; and said structural formations also defining a second series of camming surfaces with one such surface located in lateral juxtaposition to each of said drawers and arranged to be moved by rotation of said rod in said first direction to a position in direct alignment with the rearward portion of the abutment means on the drawer which has been extended to an open position, such that upon returning said drawer to its closed position said abutment means rearward portion will contact and push against such camming surface in said second series to rotate said rod in a second direction back to its initial position.

2. The improvement in file cabinets recited in claim 1, wherein said structural formations define a plurality of said indexing and blocking surfaces, one such surface being located in lateral juxtaposition to each of said drawers.

3. The improvement in file cabinets recited in claim 2, wherein each of said indexing and blocking surfaces is located generally in blocking alignment with respect to the abutment means on the drawer to which such surface is in lateral juxtaposition when said rod is in its said initial position and such drawer then occupies an open position, and wherein said interlock means further includes means operative in response to the closing of such drawer to move at least one of each such aligned indexing and blocking surface and abutment means to relatively move the two out of said blocking alignment and thereby permit such drawer to be closed.

4. The improvement in file cabinets recited in claim 3, wherein said means operative in response to the closing of such drawer includes a cam portion on said abutment means and a cam follower portion defined by said structural formations, said cam portion contacting said follower portion to move the same upon closing of said drawer.

5. The improvement in file cabinets recited in claim 4, wherein said cam portion and cam follower portion are arranged to move said rod upon closing of said drawer.

6. The improvement in file cabinets recited in claim 1, further including resilient biasing means coupled to said rod for holding the same at at least one of the limits its said first and second directions of rotary movement.

7. The improvement in file cabinets recited in claim 6, wherein said resilient biasing means is arranged to hold said rod at either of its limits of rotary movement when said rod has been brought to one or the other such limit.

8. The improvement in file cabinets recited in claim 7, wherein said resilient biasing means comprises a spring element arranged to operate in an over-center manner.

9. The improvement in file cabinets recited in claim 1, wherein at least some of said structural formations on said rod comprise rigid finger elements projecting laterally outwardly from said rod.

10. The improvement in file cabinets recited in claim 9, wherein at least some of said finger elements define on their outer periphery more than a single one of the surfaces in the group including said first camming surfaces, said interlock surfaces, and said second camming surfaces.

11. The improvement in file cabinets recited in claim 1, wherein at least some of said structural formations on said rod comprise a pair of angularly disposed rigid finger elements projecting laterally outwardly from said rod.

12. The improvement in file cabinets recited in claim 11, further including resilient biasing means coupled to said rod for holding the same at at least one of the limits its said first and second directions of rotary movement.

13. The improvement in file cabinets recited in claim 11, wherein one of the angularly disposed finger elements in each of said pairs thereof defines an indexing and blocking surface.

14. The improvement in file cabinets recited in claim 13, wherein each of said finger elements in said pairs thereof defines on its outer periphery two of the surfaces in the group including said first camming surfaces, said indexing and blocking surfaces, said interlock surfaces and said second camming surfaces.

15. The improvement in file cabinets recited in claim 14, wherein said resilient biasing means is arranged to hold said rod at either of its limits of rotary movement when said rod has been brought to one or the other such limit.

16. The improvement in file cabinets recited in claim 15', wherein one of said finger elements in each of said pairs defines on its outer periphery one of said first camming surfaces and one of said indexing and blocking surfaces and the other one of said finger elements in each such pair defines one of said interlock surfaces and one of said second camming surfaces.

17. The improvement in file cabinets recited in claim 16, wherein said resilient biasing means comprises a spring element arranged to operate in an over-center manner.

18. The improvement in file cabinets recited in claim 17, wherein said rod includes an offset portion extending laterally of the longitudinal axis of the rod, and said spring element is a coil spring connected between such oifset portion and said cabinet such that the longitudinal axis of the spring is shiftable across the said longitudinal axis of the rod.

19. The improvement in file cabinets recited in claim 16, wherein said abutment means for said drawers comprises a lateral extension securable to each such drawer and having spaced forward and rearward edge surfaces comprising said portions for contacting said camming surfaces in said first and second series thereof.

20. The improvement in file cabinets recited in claim 19, wherein said lateral extension is a V-shaped element, having angularly-disposed sides forming said forward and rearward edge surfaces.

21. The improvement in file cabinets recited in claim 20, wherein each of said indexing and blocking surfaces is located generally in blocking alignment with respect to the abutment means on the drawer to which such surface is in lateral juxtaposition when said rod is in its said initial position and such drawer then occupies an open position, and wherein said interlock means further includes means operative in response to the closing of such drawer to move at least one of each such aligned indexing and blocking surface and abutment means to relatively move the two out of said blocking alignment and thereby permit such drawer to be closed.

22. The improvement in file cabinets recited in claim 21, wherein said means operative in response to the closing of such drawer includes a cam portion on said abutment means and a cam follower portion defined by said structural formations, said cam portion contacting said follower portion to move the same upon closing of said drawer.

23. The improvement in file cabinets recited in claim 22, wherein said cam portion and cam follower portion are arranged to move said rod upon closing of said drawer.

24. The improvement in file cabinets recited in claim 23, wherein said cam portion comprises a vertically slop ing surface on said rearward portion of each of said abutment means and said cam follower portion comprises a surface portion on the finger element in each of said pairs which defines said first camming surface and said indexing and blocking surface.

25. The improvement in file cabinets recited in claim 24, wherein said finger element is elevated with respect to the other such finger element in each particular pair thereof.

References Cited UNITED STATES PATENTS 2,719,770 10/ 1955 Roberts 312221 2,842,419 7/1958 Howard 312218 2,992,056 7/ 1961 Thielker 312-221 3,150,902 9/1964 Naab et a1 3l2-250 X 3,259,444 7/ 1966 Friend 312-221 3,323,849 6/1967 Stark 312221 3,371,974 3/1968 Vermeersch 312-2118 CASMIR A. NUNBERG, Primary Examiner. 

